Search

Background/Objectives: The dairy industry relies on reproductive efficiency to maintain efficient milk production. Spontaneous abortion (SA), defined as pregnancy loss between gestation days 42 and 260, occurred in 4.5% of the artificially inseminated (AI) Holstein heifers and 31.6% of the embryo transfer (ET) recipient Holstein heifers that received in vitro-produced frozen embryos on a single dairy farm in Idaho. Methods: A genome-wide association analysis (GWAA) was performed to identify the associations (FDR p < 0.05) with SA in heifers that were bred by AI (1351 controls that delivered at term and 63 cases that aborted) that conceived following the first insemination, as well as in 59 controls and 273 cases of ET recipient heifers pregnant from the first ET. Results: There were 216 loci and 413 positional candidate genes associated (FDR p < 0.05) with SA in the heifers bred by AI in a recessive model and no loci associated with SA in the ET recipients. Conclusions: The identification of loci associated with SA in the heifers bred by AI may be used to reduce fetal loss through genomic selection. [ABSTRACT FROM AUTHOR]

Introduction: Reproductive efficiency in dairy cattle bred by artificial insemination (AI) or via embryo transfer (ET) is important as a means of facilitating the rate of genetic improvement by utilizing superior genetics from sires and donor dams. Fertility is especially challenging in primiparous cows as they have recently calved, are still growing, and are lactating. Fertility, measured by the conception rate from the first service (CCR1), is the number of cows that become pregnant as a result of the first AI or ET compared to all cows serviced, whereas times bred (TBRD) is the number of inseminations cows bred by AI needed to achieve a successful pregnancy. Methods: This study aimed to identify the loci associated with and gene sets enriched for the CCR1 in primiparous cows that were bred by AI (n = 882) or were ET recipients (n = 353), and to identify the loci associated with the TBRD (n = 1,851) in primiparous cows. A genome-wide association analysis and gene set enrichment analysis were performed using single-nucleotide polymorphism (SNP) data for the CCR1 and TBRD in primiparous cows. In cows bred by AI, two loci containing five positional candidate genes were associated with the CCR1 (p < 1 × 10−5) and one gene set with 18 leading-edge genes was enriched (NES ≥3) for the CCR1. Results and discussion: In cows that were ET recipients, five loci were associated with the CCR1, but no gene sets were enriched for the CCR1. For the second phenotype, five loci with nine positional candidate genes were associated with the TBRD and two gene sets with eight leading-edge genes were enriched for the TBRD. Identifying the loci associated with or gene sets enriched for the CCR1 and TBRD provides an opportunity to better understand embryonic loss in AI-bred and ET-recipient cows and to use this information to select for higher reproductive efficiency. [ABSTRACT FROM AUTHOR]

Bovine respiratory disease (BRD) is the most common infectious disease of beef and dairy cattle and is characterized by a complex infectious etiology that includes a variety of viral and bacterial pathogens. We examined the global changes in mRNA abundance in healthy lung and lung lesions and in the lymphoid tissues bronchial lymph node, retropharyngeal lymph node, nasopharyngeal lymph node and pharyngeal tonsil collected at the peak of clinical disease from beef cattle experimentally challenged with either bovine respiratory syncytial virus, infectious bovine rhinotracheitis, bovine viral diarrhea virus, Mannheimia haemolytica or Mycoplasma bovis. We identified signatures of tissue-specific transcriptional responses indicative of tropism in the coordination of host's immune tissue responses to infection by viral or bacterial infections. Furthermore, our study shows that this tissue tropism in host transcriptional response to BRD pathogens results in the activation of different networks of response genes. The differential crosstalk among genes expressed in lymphoid tissues was predicted to be orchestrated by specific immune genes that act as 'key players' within expression networks. The results of this study serve as a basis for the development of innovative therapeutic strategies and for the selection of cattle with enhanced resistance to BRD.

Bovine respiratory disease complex (BRDC) is an important cause of mortality and morbidity in cattle; costing the dairy and beef industries millions of dollars annually, despite the use of vaccines and antibiotics. BRDC is caused by one or more of several viruses (bovine respiratory syncytial virus, bovine herpes type 1 also known as infectious bovine rhinotracheitis, and bovine viral diarrhea virus), which predispose animals to infection with one or more bacteria. These include: Pasteurella multocida, Mannheimia haemolytica, Mycoplasma bovis, and Histophilus somni. Some cattle appear to be more resistant to BRDC than others. We hypothesize that appropriate immune responses to these pathogens are subject to genetic control. To determine which genes are involved in the immune response to each of these pathogens it was first necessary to experimentally induce infection separately with each pathogen to document clinical and pathological responses in animals from which tissues were harvested for subsequent RNA sequencing. Herein these infections and animal responses are described.

BackgroundBovine respiratory disease complex (BRDC) is an infectious disease of cattle that is caused by a combination of viral and/or bacterial pathogens. Selection for cattle with reduced susceptibility to respiratory disease would provide a permanent tool for reducing the prevalence of BRDC. The objective of this study was to identify BRDC susceptibility loci in pre-weaned Holstein calves as a prerequisite to using genetic improvement as a tool for decreasing the prevalence of BRDC. High density SNP genotyping with the Illumina BovineHD BeadChip was conducted on 1257 male and 757 female Holstein calves from California (CA), and 767 calves identified as female from New Mexico (NM). Of these, 1382 were classified as BRDC cases, and 1396 were classified as controls, with all phenotypes assigned using the McGuirk health scoring system. During the acquisition of blood for DNA isolation, two deep pharyngeal and one mid-nasal diagnostic swab were obtained from each calf for the identification of bacterial and viral pathogens. Genome-wide association analyses were conducted using four analytical approaches (EIGENSTRAT, EMMAX-GRM, GBLUP and FvR). The most strongly associated SNPs from each individual analysis were ranked and evaluated for concordance. The heritability of susceptibility to BRDC in pre-weaned Holstein calves was estimated.ResultsThe four statistical approaches produced highly concordant results for 373 top ranked SNPs that defined 126 chromosomal regions for the CA population. Similarly, in NM, 370 SNPs defined 138 genomic regions that were identified by all four approaches. When the two populations were combined (i.e., CA + NM) and analyzed, 324 SNPs defined 116 genomic regions that were associated with BRDC across all analytical methods. Heritability estimates for BRDC were 21% for both CA and NM as individual populations, but declined to 13% when the populations were combined.ConclusionsFour analytical approaches utilizing both single and multi-marker association methods revealed common genomic regions associated with BRDC susceptibility that can be further characterized and used for genomic selection. Moderate heritability estimates were observed for BRDC susceptibility in pre-weaned Holstein calves, thereby supporting the application of genomic selection to reduce the prevalence of BRDC in U.S. Holsteins.

Abstract Background In 2006, an atypical U.S. case of bovine spongiform encephalopathy (BSE) was discovered in Alabama and later reported to be polymorphic for glutamate (E) and lysine (K) codons at position 211 in the bovine prion protein gene (Prnp) coding sequence. A bovine E211K mutation is important because it is analogous to the most common pathogenic mutation in humans (E200K) which causes hereditary Creutzfeldt – Jakob disease, an autosomal dominant form of prion disease. The present report describes a high-throughput matrix-associated laser desorption/ionization-time-of-flight mass spectrometry assay for scoring the Prnp E211K variant and its use to determine an upper limit for the K211 allele frequency in U.S. cattle. Results The K211 allele was not detected in 6062 cattle, including those from five commercial beef processing plants (3892 carcasses) and 2170 registered cattle from 42 breeds. Multiple nearby polymorphisms in Prnp coding sequence of 1456 diverse purebred cattle (42 breeds) did not interfere with scoring E211 or K211 alleles. Based on these results, the upper bounds for prevalence of the E211K variant was estimated to be extremely low, less than 1 in 2000 cattle (Bayesian analysis based on 95% quantile of the posterior distribution with a uniform prior). Conclusion No groups or breeds of U.S. cattle are presently known to harbor the Prnp K211 allele. Because a carrier was not detected, the number of additional atypical BSE cases with K211 will also be vanishingly low.

Consumption of an adequate volume of high-quality colostrum soon after birth is critical for a calf's health. Few studies have focused on the genetics associated with colostrum production, even though several dairy herds in the United States have reported incidents of low to no colostrum production during the fall and winter seasons. The objectives of this study were to identify loci associated with quantity and quality of colostrum production in a herd of Jersey cattle (n = 345) and to identify potential positional candidate genes and/or transcription factor binding site motifs located near associated loci. Cattle that freshened between the months of October and December of 2016 at a single dairy were enrolled in the study and produced on average 3.03 kg of colostrum at their first milking. This study included 112 cattle genotyped with the GeneSeek GGP50k BeadChip and another 233 cattle previously genotyped with various other arrays. The 233 cattle genotyped at lower densities were imputed to the GGP50k BeadChip density using BEAGLE 4.1.1, and 2 genome-wide association analyses (GWAA) were conducted using an additive efficient mixed-model association expedited method with a genomic relationship matrix (EMMAX-GRM). The first GWAA investigated loci associated with colostrum quantity and identified 7 loci: 6 that were moderately associated (5 × 10−07 > P < 1 × 10−05) and 1 that was strongly associated (P < 5 × 10−07). The second GWAA investigated colostrum quality and identified 1 moderately (5 × 10−07 > P < 1 × 10−05) associated locus. Five loci harbored positional candidate genes which had functional relevance to colostrum production, and 1 locus located on BTA10 contained a transcription factor binding site motif for TFAP2A which has previously been linked to mammary gland development. Pseudoheritability estimates were moderate for colostrum quality (0.19 ± 0.06) and high for colostrum quantity (0.76 ± 0.11), suggesting that genomic selection for these traits would be possible. Diminished colostrum quantity or quality can have a significant impact on herd health and herd economics. The identification of loci, positional candidate genes, and transcription factor binding site motifs associated with colostrum production could be used in genomic selection to allow producers to select for cattle with good colostrum production, improving calf health, and reducing economic losses to the herd. [ABSTRACT FROM AUTHOR]

Although purebred cattle producers have had genomic EPDs for over a decade, crossbred commercial beef cattle producers have not had the opportunity to use genomic selection for improvement of their cattle. This study aimed to identify what is needed to facilitate the adoption of genomic selection in crossbred beef herds through a survey of beef cattle associations in the western United States. Surveys were distributed electronically through state cattlemen's associations in Arizona, Idaho, Nevada, Utah, Washington and Wyoming. Nineteen individuals completed the survey representing predominantly cow/calf operations (68%), followed by stockers (9%), feedlots (5%), raising of replacement heifers (5%), and a seedstock producer (5%). Most beef producers (74%) had heard about genomic selection, but only 26% had utilized genomic selection. Of those who had previously used genomic selection, most (60%) were cow/calf producers. Those using genomic selection had done so to identify superior animals (33%), to select replacement heifers (25%) or to identify calf parentage (17%). The use of genomic selection to reduce or manage financial risk or to choose AI bulls for mating selection could expand the value of genomic selection for the beef producer while increasing the rate of genetic improvement in their herd. Interests and concerns regarding genomic selection were also identified, which can be utilized to identify areas of extension and outreach that need to be improved for the technology to be adopted and used more effectively. Key topics needed for genomic selection to be adopted were confirming that genomic selection resulted in a positive return on investment, being able to confidently interpret genomic EPDs, learning how to fully use the genomic EPD results, and information regarding the accuracy of the genomic selection results. The potential for genomic selection within the beef industry is immense, and this survey confirmed that extension programs on genomic selection use have the opportunity to be beneficial to commercial beef producers throughout the industry to improve the genetics of their herds while reducing their financial risk. [ABSTRACT FROM AUTHOR]

Genomic selection is a tool available to the dairy industry, capable of increasing economic returns through improved efficiencies and selection of superior animals. However, these tools are underutilized within the commercial sector, mostly due to a lack of information on how to effectively use them. The objective of this work was to provide producers and veterinarians with educational workshops that included information about genomic selection and evaluate the impact of these workshops on participant receptivity towards using genomic selection tools. Three workshops were held in both Washington and Idaho for industry personnel and veterinarians. Thirty-six individuals attended the workshops and completed a pre-workshop survey to capture their understanding of genomic selection and its uses, as well as information regarding their current usage or interest in the technology. After attending a discussion on the basics of genomic selection, various uses and benefits, and then applying the information to an example herd, participants were asked to complete the same survey. In addition to the initial questions, participants were polled to determine if their opinions surrounding genomic selection had changed and if the workshop was beneficial. A third survey on skills gained and applicability of information was also completed. Before the workshop, 59% reported that they have used genomic selection, 54% stated they would use genomics to select replacement heifers, and 73% would use genomics to make breeding decisions. When comparing pre- and post-workshop survey responses using a t-test, the mean score increased (P = 0.0027) from 83% to 94%. When gauging the success of the workshop, 87% stated they found the workshop helpful and 80% said they would like more information. All individuals stated they will either be using genomic selection in the future (57%) or would consider the technology (43%). Producers in attendance manage over 20,600 cows and 6,600 replacement heifers. Attending veterinarians provided consultations for > 56,000 cows and 30,800 heifers. Moreover, attendees estimated they would discuss the workshop with approximately 240 other individuals. These workshops provide a basis for establishing hands-on learning for industry members to gain information on technologies that can be used to improve their respective businesses. The use of genomic selection could grow exponentially if producers and supporting individuals are given access to educational events and materials to allow for better understanding of how to use the technology to its maximum ability. Funding for this project (# SW21-925) was provided by the Western Sustainable Agriculture Research and Education. [ABSTRACT FROM AUTHOR]

Wagyu cattle have gained popularity in recent years due to their increased amounts of intramuscular marbling and their calving ease in crossbred cattle. The small effective population size of Wagyu cattle outside of Japan has led to inbreeding and an increased presentation of autosomal recessive traits. Cryptorchidism, the absence of at least one testicle from the scrotum, is the most common genital defect in males and is seen more commonly in inbred populations suggesting an autosomal recessive inheritance. The objective of this study was to identify genetic regions associated with unilateral cryptorchidism in related Wagyu cattle. All individuals in the study shared a common cow ancestor in their pedigree. Fourteen individuals, three cases and eleven controls, were genotyped using the Illumina BovineHD BeadChip (San Diego, CA). There were 450,083 SNPs that remained for the haplotype analysis after SNPs were removed for quality control parameters of genotyping call rate (< 90%), minor allele frequency (< 1%) and failure to meet Hardy Weinberg equilibrium testing (P < 1 x 10-5). No animals were removed due to low call rate (< 90%). Haplotypes were detected within the SNP and Variation Suite v8.2 (Golden Helix, Bozeman, MT) for an association with cryptorchidism using a chi-square test (P < 0.05) and false discovery rate (FDR < 0.05). There were 107,439 different SNP haplotype combinations among 49,627 haplotypes identified in the Wagyu cattle. The average haplotype size was 21.7 kb in Wagyu cattle. Prior to multiple testing correction, 1,233 haplotypes were associated (P < 0.05), with 6 haplotypes on BTA7 (P = 0.001 to P = 0.002) being of particular interest as the SNPs for those haplotypes were identical and homozygous, whereas none of the controls were homozygous for the SNPs. The SNP haplotype pattern observed on BTA7 was consistent with an autosomal recessive trait. When applying multiple testing corrections (FDR < 0.05), none of the haplotypes were significant. Additional unilateral cryptorchid bulls that share the same common cow ancestor have been identified and will be tested to see if the haplotypes on BTA7 are segregating with the phenotype. Identifying genetic regions associated with cryptorchidism will allow the identification of carriers for this trait that can then be used for choosing mates that are not carrying this trait. Reducing the number of cryptorchid males in a breed with a small effective population size would allow breeders to utilize the genetics of carriers without increasing the frequency of cryptorchidism. [ABSTRACT FROM AUTHOR]